1. Field of the Invention
The present invention relates generally to high pressure valves and more particularly to a positive acting, highly reliable high pressure fill and vent valve for use in filling pressure vessels.
2. Discussion of the Prior Art
A very difficult problem faced by designers of high pressure gas handling equipment has been the design of simple, yet extremely safe and highly reliable high pressure valve couplings for use in filling and venting high pressure gas systems such as pressure vessels. Of particular concern in the design of such devices has been the design of valve components which will enable the valve to be repeatedly opened and closed under high pressures ranging in thousands of pounds per square inch without the necessity of applying excessive operating forces and without experiencing leaking and other valve malfunctions.
Prior art fill and vent valves for high pressure applications have traditionally embodied valve seats and valve faces having the configuration illustrated in FIGS. 4 and 5 of the drawings. As best seen in FIG. 5, effective sealing is achieved in these types of valves by causing the valve seat to actually "bite into" the valve face along a single line of contact as the valve stem is mechanically drawn into a seating position. While such an arrangement usually provides a reasonable effective high pressure gas seal the first few times the device is opened and closed, it has significant drawbacks after multiple cycling. This is because even the first time the valve is closed damage is caused to the valve face due to the cutting or scoring action of the valve seat. Upon each subsequent closing of the valve, the damage is aggrevated making the valve potentially unsafe.
The significant drawbacks of the prior art high pressure coupling devices are eliminated in the device of the present invention. By providing a unique elongated tapered "surface to surface" seal, damage to the valve seat and valve face is completely avoided. Therefore, the device of the present invention can be used repeatedly with absolute reliability and safety. Due to the novel conically shaped mating surfaces of the valve, wear is automatically compensated for and effective sealing, even under very high pressures, is assured.